1. Field of the Invention
This invention relates to a semiconductor device and more particularly to a novel semiconductor device capable of allowing flow of an electron current and a hole current in different direction.
2. Description of the Related Art
Various semiconductor devices have been proposed heretofore. There are those having one-dimensional structures by which an output is provided according to one transfer function f.sub.1 (V.sub.1, V.sub.2, . . . ) or f.sub.2 (I.sub.1, I.sub.2, . . . ), where V.sub.1, V.sub.2, . . . are input voltages and I.sub.1, I.sub.2, . . . are input currents, such as bipolar junction transistors, field effect transistors, thyristors, etc. There are also those having two-dimensional structures in which a potential barrier .PSI. (V.sub.1, V.sub.2) is formed in response to input voltages (V.sub.1, V.sub.2) and an output is provided according to one transfer function f.sub.3 (.PSI.) in accordance with the potential barrier .PSI.. Here, the word "two-dimensional" is used to mean the positive role of the gate and drain voltages for electrostatically controlling a potential barrier (saddle point) in the current path through different directions.
As described above, the conventional semiconductor devices have one transfer function irrespective of whether they have a one-dimensional or two-dimensional structure. The semiconductor device having only one transfer function has its own advantages and disadvantages. There is a need for a novel semiconductor device which is free from the limitations of the conventional semiconductor devices. For example, the conventional semiconductor devices have some structural limitation for raising the packing density, and there is a demand for a new device having a completely novel structure which can break through the limitation in the packing density.